Efficient fat burning metabolism is a quality most endurance athletes are seeking for in long endurance events. It will save your limited available glycogen (carbs) storage. From nature some atheletes are real carb burners. This means these athletes will need to bring up there carbs intake during long distance endurance events. Effective personalised nutrition strategies are based on the knowledge of your metabolism at race intensity.

How to measure fat / carbs metabolism?

There are two easy available methods to measure the use of fat / carbs at race intensity :

  1. Vo2max + anaerobic treshold excercise test
  2. Lactate anaerobic treshold excercise test

Both tests will do the measurement for fat and carb burning capacities. Vo2max test is mostly done at an excercise lab. The lactate test can also be done as a field test. Lactate testing is cheaper and can be done several times over the year to closely monitor improvements. In both test it is important to know your fat / carb metabolism at race intensity. At low intensity there will mostly be fat burning and at high intensity mostly carb burning. Most long endurance events will take place a little bit below the anaerobic treshold. We like to know at this intensity what your metabolism preference is to get you the best choice in race nutrition strategy.


1. Vo2max + anaerobic treshold excercise test

This test is performed during exercise. It is also called anaerobic capacity test. It provides information on different intensity levels at which your body uses oxygen and burns fat. These types of tests are done during different types of exercise. For example, if you are a biker, they would be done during a ride. For a runner during (tredmill) run.

Generally, the individual breathes into a mask during the exercise until the intensity level is too strong, or until the testing is stopped. Based on the amount of carbon dioxide that the individual exhales during each level of intensity, an estimate of how much oxygen and fat / carbs burning happens at each stage can be made.

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2. Lactate anaerobic treshold excercise test

This test is similar to the VO2 Max in built up at different intensities. It measures the lactate production from the musles in the blood. The lactate levels corresponds to usage of the different types of metabolism. Fat and/or carbs. Low amounts of lactate (below 2 mmol/l) indicates the usage of fat. Higher amounts of lactate will indicate a combination of both the energy systems (fat and carbs). High levels of lactate (above 4 mmol/l) will mainly indicatie the usage of carbs. More advanced sport coaches can do this setting and blood will be drawn at various activity levels from vinger or ear.

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